1. Field of the Invention
This invention relates to a novel polymer useful as various functional materials, a polymer-containing composition containing the same, an ink composition, and an ink applying method and an ink applying apparatus that make use of the ink composition. More particularly, this invention preferably relates to a recording material, including an ink composition, that makes use of such a polymer together with a solvent or a dispersion medium and a coloring material, and also relates to an ink applying method and an ink applying apparatus that make use of such an ink composition.
2. Related Background Art
Aqueous dispersion materials containing functional substances are conventionally well known to contain, as functional materials, agricultural chemicals such as herbicides and insecticides; pharmaceuticals such as carcinostatics, antiallergic agents and antiphlogistics; and coloring materials such as inks and toners having colorants. In recent years, digital printing technique has made very dramatic progress. This digital printing technique is, as its typical example, what is called electrophotographic technique or ink jet technique, and is more and more making its presence felt as an image forming technique used in offices, homes and so forth.
In particular, the ink jet technique has great characteristic features such as compactness and low power consumption as a direct recording method. Also, image quality is rapidly being made higher as nozzles are made finer. An example of the ink jet technique is a method in which an ink fed from an ink tank is heated with heaters in nozzles to cause evaporation to bubbling, whereupon the ink is ejected to form images on a recording medium. Another example is a method in which the ink is ejected from nozzles by vibrating piezoelectric elements.
As inks used in such methods, aqueous dye solutions are usually used, and hence colors may blur when they are superimposed, or a phenomenon called feathering may occur in the direction of fibers of paper at recorded areas on a recording medium. For the purpose of making improvements on these, the use of pigment-dispersed inks has been studied (see U.S. Pat. No. 5,085,698). In a reported example of a pigment dispersing method, a polymer having a sulfonic group is used (see U.S. Pat. No. 5,713,993). However, there remains a need to make more improvements.
In the production of ink compositions or toner compositions, it has also conventionally frequently been put into practice to disperse a coloring material in a solution in which a binder resin has been dissolved. In general, styrylic, acrylic or methacrylic polymers are used as binder resins used in dispersing pigments by the wet process. Then, in preparing pigment inks composed of a solvent, in particular, water as a base material, it is considered preferable to use a high-molecular material having an ionic functional group.
Meanwhile, a polymer having a polyalkenyl ether backbone chain is also known as a high-molecular material having a flexible high-molecular chain. It, however, is little put into practice to introduce an ionic functional group into a repeating unit of such a polymer. A disclosure is slightly seen on a carboxylic acid and an ester thereof as one having a possibility therefor (see Journal of Polymer Science Part A, Polymer Chemistry, Vol. 27, pp. 3303-3314, 1989). Under the existing conditions, however, it is sought to provide a stabler polymer.